No the Government is not purposely a scheming organization trying to manipulate the average person. Before I lay down a systematic argument however there are a few terms that need defining and the topic needs to be significantly less broad. To begin, the term government means no more or less than the group of people with the authority to govern a country or state. Benefit refers to acquiring an advantage or upper hand.
Advertisement has a very broad definition but in this context it means no more than an announcement to the people to buy a product, go to an event, or perform some action. This notice is nothing more than a suggestion, and it cannot be called a manipulation scheme, for that particular combination of words has a negative connotation (where one person is cunningly controlling the actions of another). People that look at advertisements have every freedom to deem them as ridiculous and disregard them. Therefore the entirety of the middle section of the argument collapses inward on itself.
Nevertheless, you as my opponent may try to state that although advertisements are not manipulation schemes, the government is still using them to benefit itself. I renounce this claim as well, but this is not due to a flaw in definitions. The purpose of government is to protect the individual rights of its citizens. At least in the United States of America the government is for the people, of the people, and by the people. The very nature of the government is that of giving the greatest quality of life possible for all people who qualify as citizens. The word "freedom" is overused but in reality, protecting freedom is the aim of the government. "The will of the people shall be the basis of the authority of government;" This is written in article 21.3 of the Universal Declaration of Human Rights. What it emphasizes is that the government is not a monstrous, sly organization looking out for it's own good, but rather a group of people (humans like you and I) that exists only to serve it's citizens; not make them slaves or robots controlled by a remote.
It also must be understood that the government uses media to help the citizens be more aware of what is going on in the world, but this is not the same as the government using advertisements to their benefit. My opponent might claim that all "Vote for me!" adds are proof of his side, but they are not. Political parties privately fund these sorts of advertisements and the government simply changes due to who wins.

I have to agree with #gretaolive because of three main aspects.
1) Not all advertisements are governmental. In fact, most of the advertisements we see on streets and on Television represent some company or NGO, who are not directly related (or controlled by) government. Now, one can say that their purpose is still earning benefit, and with that I totally agree, but the thing is that the earned profits don't go straight to government but firstly to the company itself and stock holders.
2) Government itself doesn't really advertise anything. Only major area that is controlled by it are the political campaigns that take place before elections. For those ads and posters, there are certain funds in the budget of our country, that cannot be exceeded. And they don't really earn anything directly to the government because the point of those ads is to help people decide who they want to choose as their representatives to the government to make important decisions.
3) Advertisements can be called somewhat manipulative but I still believe that people have maintained some sort of sense of reality and ability to make final decisions. We can say that advertisement business(industry) has become a major and really important source of profit and it keeps growing day by day. Companies come up with new and innovative techniques and ways to make their product stand out and get attention. And obviously, the reason behind all this is to earn money. But no matter how eye-catching, shiny, sparkly, moving, slow, any ad or commercial is, the final decision comes from the people themselves and I think that we shouldn't consider advertisements so much as a way to manipulate people rather than informative and useful in terms of giving overview of some new products or innovative ideas and solutions.